The overall objectives of the study are: 1) the isolation, purification and characterization of the antigens of animal sperm that are capable of inducing immunologic infertility and 2) the study of the immunologic mechanisms responsible for the infertility. Sperm antigens after solubilization with suitable reagents will be isolated by affinity chromatography, ion exchange chromatography and electrophoretic chromatography. Effects of isoimmunization with specific antigens will be determined in fertility processes. The cross reaction of sperm antigens with antigens of developing preimplanting embryos will be examined in several species. BIBLIOGRAPHIC REFERENCE: Menge, A.C., V. Schweitzer, A. Rosenberg, C. Westhoff. 1977. Local immunity of the female reproductive tract and infertility in rabbits. In "Immunology of Reproduction," Proc. Third Int. Symp. Bulg. Acad. Sci., Sofia.